WO2020174706A1

WO2020174706A1 - Bicycle chain drive mechanism

Info

Publication number: WO2020174706A1
Application number: PCT/JP2019/021807
Authority: WO
Inventors: 富雄柿見
Original assignee: 富雄柿見
Priority date: 2019-02-28
Filing date: 2019-05-31
Publication date: 2020-09-03
Also published as: JP6526932B1; JP2020138675A

Abstract

[Problem] To provide, with a simple overall configuration and at low production cost, a bicycle chain drive mechanism capable of transmitting drive power to a rear wheel regardless of whether the rotation direction of a crank arm is forward or reverse. [Solution] An inner sprocket 20 and an outer sprocket 24 coaxial with the inner sprocket rotate integrally with a crank shaft 12 of a bicycle, and are arranged in parallel so as to be capable of relative rotation with respect to the crank shaft 12. An inner free wheel 22 and an outer free wheel 26 coaxial with the inner free wheel rotate coaxially with a rear wheel of the bicycle, and are arranged in parallel. A chain 28 is stretched over the inner sprocket 20 and the outer sprocket 24 and the inner free wheel 22 and the outer free wheel 26 so that the outer sprocket 24 rotates in the reverse direction with respect to the inner sprocket 20 and the outer free wheel 26 rotates in the reverse direction with respect to the inner free wheel 22.

Description

Bicycle chain drive

The present invention relates to a bicycle drive mechanism, and more particularly to a bicycle chain drive mechanism that transmits a driving force to a rear wheel via a chain.

　Most of the bicycle drive devices that are widely used in general have a combination of a crank mechanism and a chain/sprocket mechanism. In this type of drive device, the driving force is transmitted to the rear wheels via a chain that revolves as the left and right crank arms rotate.

　General bicycles have a freewheel built in the rear wheels, and the torque is transmitted to the wheel axles of the rear wheels only when the left and right crank arms rotate forward. On the other hand, Patent Document 1 discloses a bicycle in which the driving force is transmitted to the rear wheels not only when the crank arm rotates in the forward direction but also when it rotates in the reverse direction.

Chinese Patent Application Publication No. 102582771

The bicycle drive device disclosed in Patent Document 1 rotates left and right crank arms in opposite directions via a bevel gear. In order to have such a configuration, it is necessary to incorporate a new mechanical element, which complicates the overall configuration and eventually increases the manufacturing cost.

In view of the above-described problems, the present invention has a simpler overall configuration than conventional ones, and at a low manufacturing cost, it is possible to transmit the driving force to the rear wheels regardless of whether the crank arm rotates in the forward or reverse direction. An object is to provide a possible bicycle chain drive mechanism.

In order to achieve the above object, a bicycle chain drive mechanism according to the present invention is provided with an inner sprocket that rotates integrally with a crankshaft of the bicycle, and an inner sprocket that is coaxial with the inner sprocket and is rotatable relative to the crankshaft. Outer sprocket, an inner freewheel that rotates coaxially with the rear wheel of the bicycle, an outer freewheel that is installed in parallel with the inner freewheel, and the outer sprocket that rotates in the opposite direction to the inner sprocket. An inner sprocket and an outer sprocket, and a chain hung on each of the inner free wheel and the outer free wheel so that the outer free wheel rotates in a direction opposite to the inner free wheel. It is characterized by

In addition, the chain is hung on the gear parts on the opposite sides of the sprocket and the freewheel on the different sides inside and outside, respectively, and the gear parts on the same side of the sprocket and the freewheel on the same side inside and outside, respectively. It is characterized by being hung on each.

Alternatively, the chain is hung on the gear parts on the opposite sides of the sprocket and the freewheel on the same side inside and outside, respectively, and the gear parts on the same top and bottom sides of the sprocket and the freewheel located on different sides inside and outside, respectively. It is characterized by being hung on each.

Also, the number of teeth of the inner sprocket and the number of teeth of the outer sprocket are the same.

Furthermore, a pedal is provided at the tip, and a left crank arm having a base end opposite to the tip is fixed to the left end of the crankshaft, and a pedal is provided at the tip, and the tip is A right crank arm having a base end portion on the opposite side attached to the right end portion of the crank shaft so as to be rotatable relative to the crank shaft; and the left crank arm, together with the inner sprocket, and the crank shaft. The right crank arm rotates integrally with the outer sprocket in a direction opposite to that of the left crank arm.

According to the chain drive mechanism for a bicycle having the above structure, the inner and outer sprockets and the inner and outer freewheels are chained so that they always rotate in opposite directions. If the cranks are rotated integrally with the inner and outer sprockets, the driving force can be transmitted to the rear wheels regardless of whether the crank arms rotate in the forward or reverse directions. In addition, since such a configuration is such that some basic components used in a general bicycle drive device are added and the mounting mode is elaborately improved, , It is not necessary to incorporate a new mechanical element (gear mechanism such as a bevel gear). Therefore, the entire configuration is simple and the manufacturing cost can be provided at low cost.

It is the (a) side view and the (b) top view showing the schematic structure of the chain drive mechanism of the bicycle concerning an embodiment. It is a schematic perspective view which shows the aspect of handling of a chain, and its movement. It is a schematic perspective view which shows the modification 1 of the aspect of handling of a chain, and its movement. It is a schematic perspective view which shows the modification 2 of the aspect of handling of a chain, and its movement. It is a schematic perspective view which shows the modification 3 of the aspect of handling of a chain, and its movement.

Hereinafter, an embodiment of a bicycle chain drive mechanism (hereinafter, simply referred to as “drive mechanism”) according to the present invention will be described with reference to the drawings.

The drive mechanism 10 according to the embodiment is one in which some basic components used in a general bicycle drive device are added, and a configuration in which the components are attached is elaborated.

As shown in FIG. 1, the drive mechanism 10 basically has the same configuration as a general bicycle drive device. That is, the configuration of the portion above the line AA indicated by the chain double-dashed line in FIG. 1B is substantially the same as that of a general bicycle drive device.

The drive mechanism 10 includes a crankshaft 12. The crankshaft 12 is axially supported inside a bottom bracket 14 fixed to a lower portion of a bicycle frame (not shown) via a bearing (not shown).

The base end of the left crank arm 16L is fixed to the left end of the crankshaft 12. A left pedal 18L is rotatably supported at the tip of the left crank arm 16L. A sprocket 20 (also called a chain wheel) is fixed to the right end side of the crankshaft 12. The left crank arm 16L fixed to the crankshaft 12 and the sprocket 20 rotate integrally with the crankshaft 12.

A freewheel 22 that rotates coaxially with the rear wheel (not shown) of the bicycle is provided behind the sprocket 20. A known ratchet mechanism is provided between the free wheel 22 and the rear wheel hub (not shown), and is configured to transmit torque only in one direction. Therefore, the torque is transmitted to the wheel axle of the rear wheel only when the freewheel 22 rotates in the same forward direction (clockwise in FIG. 1) as the direction in which the rear wheel rotates forward.

On the other hand, the structure of the portion below the line AA is different from the structure of a general bicycle drive device. Hereinafter, the configuration of this different part will be described in detail.

At the right end of the crankshaft 12, another sprocket 24 (also called a chain wheel) is provided. The sprocket 24 has the same structure as the sprocket 20. That is, the outer diameters of both

sprockets

20 and 24 are the same, and the number of teeth of the gears formed on the outer peripheral portions of each is also the same. In the following description, the sprocket 24 on the axial end side (outer side) of the crankshaft 12 is referred to as an “outer sprocket”, and the sprocket 20 on the axial center side (inner side) thereof is referred to as an “inner sprocket”. The

sprockets

20 and 24 will be distinguished.

The outer sprocket 24 is arranged coaxially with the other inner sprocket 20, and is attached to the right end portion of the crankshaft 12 via a bearing (not shown) such as a bearing or a bush. Therefore, the outer sprocket 24 is rotatable relative to the crankshaft 12, and is configured to rotate coaxially with the adjacent inner sprocket 20.

Right crank arm 16R is also attached to the right end of the crankshaft 12. A right pedal 18R is rotatably supported at the tip of the right crank arm 16R, like the left crank arm 16L. On the other hand, the base end portion of the right crank arm 16R is fixed to the outer sprocket 24. That is, in this example, the right crank arm 16R is attached to the right end portion of the crankshaft 12 via the sprocket 24 and the bearing (not shown). Therefore, when the sprocket 24 rotates relative to the crankshaft 12, the right crank arm 16R also rotates integrally with the sprocket 24.

Another freewheel 26 is also provided on the right end of the rear wheel axle. The free wheel 26 has the same structure as the free wheel 22 described above. That is, the outer diameters of both

free wheels

22 and 26 are the same, and the number of teeth of the gears formed on the outer peripheral portions of each is the same. In the following description, the free wheel 26 on the axial end side (outer side) of the wheel shaft is referred to as an “outer free wheel”, and the free wheel 22 on the axial center side (inner side) thereof is referred to as an “inner free wheel”. , The two

freewheels

22 and 26 will be distinguished.

The outer freewheel 26 is arranged coaxially with the other inner freewheel 22, and rotates coaxially with the outer freewheel 22 and then the rear wheel of the bicycle. A known ratchet mechanism is also provided between the outer free wheel 26 and the wheel axle of the rear wheel, and is configured to transmit torque only in one direction. In this example, the outer free wheel 26, like the inner free wheel 22, transmits torque to the wheel axles of the rear wheels only when the rear wheels rotate in the same forward direction (clockwise in FIG. 1) as the direction in which the rear wheels rotate forward. It is configured to be.

As described above, the drive mechanism 10 has a total of four transmission gears including two

sprockets

20 and 24 on the drive side (front side) and two

free wheels

22 and 26 on the driven side (rear side). There is. An endless chain 28 is hung on each of these four transmission gears.

The chain 28 is longer than that used in a general bicycle drive device, and is laid on each of the four transmission gears in the manner described below. The manner of handling the chain 28 will be described with reference to FIGS. 1 and 2.

The chain 28 is stretched between the upper gear portion 24U of the outer sprocket 24 and the upper gear portion 26U of the outer freewheel 26 and folded back to the lower gear portion 26L of the outer freewheel 26. The folded chain 28 is hung from the lower gear portion 26L of the outer free wheel 26 to the upper gear portion 20U of the inner sprocket 20 and folded back to the lower gear portion 20L of the inner sprocket 20. Further, the chain 28 hung from the lower gear portion 20L of the inner sprocket 20 to the lower gear portion 22L of the inner freewheel 22 is folded back to the upper gear portion 22U of the inner freewheel 22 and the outer sprocket 24 It is stretched around the lower gear portion 24L.

With this arrangement, the chain 28 hung on each of the four transmission gears of the two inner and

outer sprockets

20 and 24 and the two inner and

outer freewheels

22 and 26 has the following four positions between the drive side and the driven side. A chain portion corresponding to one section, that is, an upper moving portion 28A, a first oblique portion 28B, a lower moving portion 28C, and a second oblique portion 28D are respectively formed.

The upper moving portion 28A is a chain portion that moves in a section between the upper gear portion 24U of the outer sprocket 24 and the upper gear portion 26U of the outer freewheel 26. The first skewed portion 28B is a chain portion that skews a section between the upper gear portion 20U of the inner sprocket 20 and the lower gear portion 26L of the outer freewheel 26. The lower moving portion 28C is a chain portion that moves in a section between the lower gear portion 20L of the inner sprocket 20 and the lower gear portion 22L of the inner freewheel 22. The second slanting portion 28D is slanted in a direction intersecting the first slanting portion 28B described above with a section between the lower gear portion 24L of the outer sprocket 24 and the upper gear portion 22U of the inner freewheel 22. It is the chain part to go.

Of the above-mentioned chain parts, the chain parts (upper moving part 28A and lower moving part 28C) that are hung on the transmission gears on the same side inside and outside are hung on the gear parts on the same upper and lower sides, respectively. , Both in a plan view and in a side view. On the other hand, the chain portions (the first skewed portion 28B and the second skewed portion 28D) that are hung on the transmission gears on the different sides inside and outside are hung on the gear portions on the upside down side, respectively. They intersect with each other in both plan view and side view.

In the drive mechanism 10 having the above configuration, the right crank arm 16R always rotates in the opposite direction to the left crank arm 16L. Further, both the inner and

outer sprockets

20 and 24 on the drive side and the inner and

outer freewheels

22 and 26 on the driven side always rotate in mutually opposite directions. The movement of the drive mechanism 10 will be described with reference to FIGS. 1 and 2.

In FIG. 2, arrows indicating the rotation direction of each transmission gear and the moving direction of the chain 28 when the right crank arm 16R rotates in the positive direction are represented by solid lines, and the left crank arm 16L rotates in the positive direction. In this case, the arrows indicating the rotating direction of each transmission gear and the moving direction of the chain 28 are represented by broken lines.

First, the movement when the right crank arm 16R rotates in the forward direction will be described.

When the right crank arm 16R rotates in the forward direction, the outer sprocket 24 also integrally rotates in the forward direction, so that the upper moving portion 28A of the chain 28 moves from the outer freewheel 26 side to the outer sprocket 24 side (arrow F1). .. With the movement of the upper moving portion 28A, the outer free wheel 26 is driven to rotate in the forward direction, and as a result, the torque is transmitted to the wheel axle of the rear wheel.

When the outer freewheel 26 rotates in the forward direction, the first skewed portion 28B of the chain 28 moves from the inner sprocket 20 side to the outer freewheel 26 side (arrow F2). When the first oblique portion 28B moves, the inner sprocket 20 rotates in the opposite direction accordingly, and the left crank arm 16L also rotates in the opposite direction together with the inner sprocket 20.

When the inner sprocket 20 rotates in the opposite direction, the lower moving portion 28C of the chain 28 moves from the inner freewheel 22 side to the inner sprocket 20 side (arrow F3). With the movement of the lower moving portion 28C, the inner freewheel 22 is driven to rotate in the opposite direction, and the second oblique portion 28D of the chain 28 moves from the outer sprocket 24 side to the inner freewheel 22 side ( Arrow F4). When the second oblique portion 28D moves, the outer sprocket 24 rotates in the positive direction accordingly, and the right crank arm 16R also integrally rotates in the positive direction together with the outer sprocket 24. By such a series of flow, the chain 28 repeats the circular movement in the endless track.

Next, the movement when the left crank arm 16L rotates in the forward direction will be described.

When the left crank arm 16L rotates in the forward direction, the inner sprocket 20 also integrally rotates in the forward direction, so that the first skewed portion 28B of the chain 28 moves from the outer freewheel 26 side to the inner sprocket 20 side ( Arrow R1). With the movement of the first oblique portion 28B, the outer freewheel 26 is driven to rotate in the opposite direction, and the upper moving portion 28A of the chain 28 moves from the outer sprocket 24 side to the outer freewheel 26 side (arrow). R2).

When the upper moving portion 28A moves, the outer sprocket 24 rotates in the opposite direction accordingly, and the right crank arm 16R also rotates in the opposite direction together with the outer sprocket 24. When the outer sprocket 24 rotates in the opposite direction, the second oblique portion 28D of the chain 28 moves from the inner freewheel 22 side to the outer sprocket 24 side (arrow R3). With the movement of the second oblique portion 28D, the inner freewheel 22 is driven to rotate in the forward direction, and as a result, the torque is transmitted to the wheel axle of the rear wheel.

When the inner freewheel 22 is driven to rotate in the forward direction, the lower moving portion 28C of the chain 28 moves from the inner sprocket 20 side to the inner freewheel 22 side (arrow R4). When the lower-side moving portion 28C moves, the inner sprocket 20 rotates in the forward direction accordingly, and the left crank arm 16L also integrally rotates in the forward direction together with the inner sprocket 20. By such a series of flows, the chain 28 repeats the circular movement in the direction opposite to the above in an endless track.

As described above, according to the drive mechanism 10 according to the embodiment, the chain 28 is hung so that both the inner and

outer sprockets

20 and 24 and the inner and

outer freewheels

22 and 26 always rotate in opposite directions. The left crank arm 16L that integrally rotates with the inner sprocket 20 and the right crank arm 16R that integrally rotates with the outer sprocket 24 rotate in opposite directions, and the left and right crank

arms

16L and 16R rotate in the respective rotating directions. In either case, the torque is transmitted to the wheel axle of the rear wheel. Therefore, no matter how the occupant of the bicycle steps on the left and

right pedals

18L and 18R, the driving force can be transmitted to the rear wheels.

Thus, for example, a wide range of modes according to the occupant's preference, such as foot pedaling in which the left and

right pedals

18L and 18R are alternately depressed, and the position in which the

pedals

18L and 18R are depressed while the bicycle is traveling. You will be able to select the pedaling operation. Alternatively, the position where the

pedals

18L, 18R are depressed is determined in advance, and a new element of play, for example, competition by a relay system is added to the bicycle. Also, since the muscles used vary depending on the mode of pedaling, it is possible to disperse the load during running and to expect a wide range of practical applications such as application to muscle training.

Further, since the drive mechanism 10 is obtained by adding some basic components used in a general bicycle drive device and improving the attachment mode by devising the device, it is described in the background art. It is not necessary to incorporate a new mechanical element (a gear mechanism such as a bevel gear) unlike the bicycle drive device disclosed in Patent Document 1. Therefore, it is advantageous in that the entire structure is simple and the manufacturing cost can be provided at low cost.

Although the chain drive mechanism for a bicycle according to the present invention has been described above based on the embodiment, the present invention is not limited to the above-described embodiment, and may be carried out in the following modified embodiment, for example. I don't mind.

It should be noted that, also in FIGS. 3 to 5 showing modified examples 1 to 3 described below, the rotation direction of each transmission gear and the moving direction of the chain 28 when the right crank arm 16R rotates in the positive direction are similar to FIG. The arrow shown is shown by a solid line, and the arrow showing the rotation direction of each transmission gear and the moving direction of the chain 28 when the left crank arm 16L rotates in the forward direction is shown by a broken line.

<Modification 1>
In the above-described embodiment, the chain 28 is routed in such a manner that the vertical relationship between the chain portion engaged with the transmission gears on the same side inside and outside and the chain portion engaged with the transmission gears on different sides inside and outside is reversed. It may be in the form of

In this case, as shown in FIG. 3, the upper moving portion 28A of the chain 28 moves in the section between the upper gear portion 20U of the inner sprocket 20 and the upper gear portion 22U of the inner freewheel 22, and the lower moving portion 28C moves in a section between the lower gear portion 24L of the outer sprocket 24 and the lower gear portion 26L of the outer freewheel 26. The first skewed portion 28B of the chain 28 skews the section between the lower gear portion 20L of the inner sprocket 20 and the upper gear portion 26U of the outer freewheel 26, and the second skewed portion 28D. Runs obliquely in a direction that intersects with the first oblique portion 28B in a section between the upper gear portion 24U of the outer sprocket 24 and the lower gear portion 22L of the inner freewheel 22. Furthermore, the direction in which each chain portion moves (skews) when the left crank arm 16L rotates in the forward direction and when the right crank arm 16R rotates in the forward direction is opposite to that in the above embodiment.

<Modification 2>
Further, in the above-described embodiment, the chain 28 is routed on the inner and outer sides of the

sprocket

20, 24 and the

freewheels

22, 26 on the same side, respectively, on the upside-down side gear parts, and on the different sides inside and outside. The

sprocket

20 and 24 and the

free wheels

22 and 26 may be respectively engaged with the gear parts on the same upper and lower sides.

In this case, as shown in FIG. 4, the upper moving portion 28A of the chain 28 moves in the section between the upper gear portion 24U of the outer sprocket 24 and the upper gear portion 22U of the inner freewheel 22, and the lower moving portion 28C moves in a section between the lower gear portion 20L of the inner sprocket 20 and the lower gear portion 26L of the outer freewheel 26. Further, the first skewed portion 28B of the chain 28 skews a section between the upper gear portion 20U of the inner sprocket 20 and the lower gear portion 22L of the inner freewheel 22, and the second skewed portion 28D. Runs obliquely in a direction intersecting the first oblique portion 28B in a section between the lower gear portion 24L of the outer sprocket 24 and the upper gear portion 26U of the outer freewheel 26. The direction in which each chain portion moves (skews) when the left crank arm 16L rotates in the forward direction and when the right crank arm 16R rotates in the forward direction is the same as in the above embodiment.

<Modification 3>
Further, in Modification 2 described above, the routing of the chain 28 is similar to Modification 1 described above, in that the chain portion that is engaged with the transmission gears on the same side inside and outside and the transmission gears that are on the different sides inside and outside are engaged with each other. The vertical relationship of each chain portion may be reversed.

In this case, as shown in FIG. 5, the upper moving portion 28A of the chain 28 moves in the section between the upper gear portion 20U of the inner sprocket 20 and the upper gear portion 26U of the outer freewheel 26, and the lower moving portion 28C moves in a section between the lower gear portion 24L of the outer sprocket 24 and the lower gear portion 22L of the inner freewheel 22. Further, the first skewed portion 28B of the chain 28 skews a section between the lower gear portion 20L of the inner sprocket 20 and the upper gear portion 22U of the inner freewheel 22, and the second skewed portion 28D. Runs obliquely in a direction intersecting the first oblique portion 28B with a section between the upper gear portion 24U of the outer sprocket 24 and the lower gear portion 26L of the outer freewheel 26. Furthermore, the direction in which each chain portion moves (skews) when the left crank arm 16L rotates in the forward direction and when the right crank arm 16R rotates in the forward direction is opposite to that in the second modification. ..

Even in the manner of handling the chain 28 as in the modified examples 1 to 3, as in the above-described embodiment, the chain 28 is either the inner and

outer sprockets

20 or 24 or the inner and

outer freewheels

22 and 26. Since the peach is always hung so as to rotate in the opposite direction, the same operation and function as those of the above-described embodiment are exhibited.

<Other modifications>
(1) In the above embodiment, the inner and

outer freewheels

22 and 26 have the same configuration, that is, the gears formed on the outer diameter and the outer periphery have the same number of teeth, but they have the same configuration. No need.

(2) In the above embodiment, the left and right crank

arms

16L and 16R are overlapped in a side view when they are in a horizontal posture, but the rotation phase in which they are overlapped is not particularly limited. For example, the rotational phase where they overlap can be appropriately set according to the occupant's preference, such as being set at a position shifted by 45° from the horizontal posture.

The present invention can be implemented in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Further, within the scope of producing the same action or effect, any of the matters specifying the invention may be replaced with another technique.

The chain drive mechanism for a bicycle according to the present invention is applicable not only to a general two-wheeled bicycle but also to a bicycle with three or more wheels.

10 Bicycle chain drive mechanism 20 Inner sprocket 22 Inner freewheel 24 Outer sprocket 26 Outer freewheel 28 Chain

Claims

An inner sprocket that rotates integrally with the bicycle crankshaft,
An outer sprocket arranged coaxially with the inner sprocket so as to be rotatable relative to the crankshaft,
An inner freewheel that rotates coaxially with the rear wheel of the bicycle,
An outer freewheel arranged in parallel with the inner freewheel,
The inner sprocket and the outer sprocket, and the inner freewheel and the outer sprocket so that the outer sprocket rotates in the opposite direction to the inner sprocket and the outer freewheel rotates in the opposite direction to the inner freewheel. A chain hung on each of the outer freewheels,
A bicycle chain drive mechanism comprising:
The chain is
The sprocket and the freewheel on the different sides inside and outside are respectively hung on the gear parts on the upside down side,
The bicycle chain drive mechanism according to claim 1, wherein the sprocket and the free wheel on the same side inside and outside are respectively hung on the gear parts on the same side in the vertical direction.
The chain is
The sprocket and the freewheel on the same side inside and outside are respectively hung on the gear parts on the upside down side,
The chain drive mechanism for a bicycle according to claim 1, wherein the sprocket and the free wheel on different sides inside and outside are respectively hung on the gear parts on the same upper and lower sides.
The bicycle chain drive mechanism according to any one of claims 1 to 3, wherein the number of teeth of the inner sprocket and the number of teeth of the outer sprocket are the same.
A pedal is provided at the tip, and the base end opposite to the tip is fixed to the left end of the crankshaft, and a left crank arm,
A pedal is provided at the distal end, and a base end opposite to the distal end is attached to the right end of the crankshaft so as to be rotatable relative to the crankshaft.
Further equipped with,
The left crank arm rotates integrally with the crank shaft together with the inner sprocket,
The bicycle chain drive mechanism according to any one of claims 1 to 4, wherein the right crank arm rotates integrally with the outer sprocket in a direction opposite to the left crank arm.